I'd be curious about dynamic range and the ability for B&W conversion.
I'd imagine that the fairly substantial sensor improvements would have to equate to greater DR, but I haven't seen any specific discussion of that, let alone comparing the two cameras specifically. But it should be a safe bet that the Sony is gonna have more DR.
B&W conversion? I don't know how the Sony's B&W jpegs are but I can't imagine the color files from the camera wouldn't be just as good as the GRD files for conversion. The GRD "grit" wouldn't be as organic in the Sony, but I'm sure its achievable.
To me the advantage to the current GRDs over this or just about any other similar small camera are all down to interface and controls and, to a lesser extent, the fixed lens. In terms of everything else, the technology is moving forward and it sure doesn't seem to be getting worse! So I'd say the advantage should be with the Sony in terms of just about anything else.